WASHINGTON (AP) — In a case that revealed underhanded tactics used to get Vincent Gray elected mayor of Washington, a former Gray campaign aide pleaded guilty Tuesday to funneling campaign funds to another mayoral candidate and shredding records of the transactions.

Thomas Gore admitted in U.S. District Court that he converted excessive or unattributed cash contributions to Gray’s 2010 campaign into money orders that were then filled out by another party and given to Sulaimon Brown, a minor candidate. The payments were intended to keep Brown in the race so that he could continue making negative comments about then-mayor Adrian Fenty as he sought reelection, Gore acknowledged.

The 56-year-old Gore, a longtime friend of Gray’s and the acting treasurer for the campaign, also admitted that he lied to the FBI about having shredded a spiral notebook in which he kept records of the payments to Brown. He further revealed that he was caught in the lie when confronted with wiretap evidence.

Brown has long maintained that he was paid by Gray’s campaign and promised a job in the Gray administration in exchange for his harsh rhetoric about Fenty. He alleged that Gray was aware of the payments, which the mayor denies. Brown was appointed to a $110,000-a-year city government job in January 2011, shortly after Gray took office, and fired after less than a month.

“In 2010, the voters of the District of Columbia were deceived,” U.S. Attorney Ronald Machen said in a statement. “Envelopes stuffed with fraudulent money orders prevented the public from knowing that one mayoral campaign was secretly financing the campaign of an opposing candidate.”

Gore pleaded guilty to a felony obstruction-of-justice charge for the attempted cover-up and three misdemeanors of making a contribution in the name of another person. The money orders contained the names of people who did not contribute to the Brown campaign.

Federal sentencing guidelines call for him to receive 12 to 18 months in prison, although prosecutors could seek a reduction in the event of “substantial cooperation” with investigators. Because of the ongoing probe, no sentencing date was set.

Gore and his attorney, Frederick Cooke, declined to comment after the hearing. Gray’s spokesman deferred comment to the mayor’s attorney, who could not be reached and has repeatedly declined to comment about the investigation.

Gray, 69, defeated Fenty by 10 percentage points in the 2010 Democratic primary, tapping into widespread dissatisfaction with a mayor widely perceived as aloof. Gray also touted himself as the more ethical candidate, criticizing Fenty for steering lucrative government contracts to his college fraternity brothers. Voters split along racial and socioeconomic lines, with Gray carrying poorer, majority-black sections of the city by wide margins while Fenty fared well in wealthier neighborhoods.

Several Gray campaign staffers have said Brown’s attacks on Fenty at candidate forums amounted to a sideshow that did nothing to help Gray get elected.

According to a document outlining Gore’s actions, which he acknowledged in court was accurate, Gore and another Gray campaign staffer agreed in June 2010 to start funneling money to Brown. Although the other campaign staffer was identified in the document only as “Person A,” records of the money-order contributions indicate that person was Howard Brooks, a Gray campaign consultant. Brooks has not been charged.

Although the guilty plea only covered three money orders, Gore acknowledged converting cash given to the Gray campaign into five money orders worth a total of $660. Three of those were in the name of Brooks’ son, Peyton Brooks, and two others contain the names of a relative of Howard Brooks and a friend of Peyton Brooks.

The documents indicate that Howard Brooks handed the money orders to Brown, which is consistent with Brown’s account of the payments.

Gore also acknowledged that he met with Howard Brooks last September to discuss the investigation. Gore told Brooks during that meeting that he shredded his records of payments to Brown after The Washington Post reported Brown’s allegations in March 2011.

When U.S. District Judge Colleen Kollar-Kotelly quoted Gore’s statements from the meeting with Brooks and asked if they were accurate, Gore said, “That was a statement taken from a wire.”

The comment indicates that Howard Brooks was working for the FBI and carrying a recording device during the meeting with Gore. Brooks’ attorney, Glenn Ivey, did not immediately return a message seeking comment.

Gore sat for a voluntary interview with the FBI in October and lied about the conversation with Brooks, telling agents that he did not keep records of money given to Brown. During the same interview, he later acknowledged the existence of the notebook but lied about when he shredded it. Gore admitted the false statements in court Tuesday.

The federal probe has cast a cloud over district government since shortly after Gray took office. Council Chairman Kwame Brown is also the subject of a federal investigation for activities during his 2008 campaign, and former councilmember Harry Thomas Jr. is heading to prison for three years for embezzling money from the city.

Tom Lindenfeld, a political consultant who worked on both of Fenty’s mayoral campaigns, said the investigation is likely to imperil city government for the foreseeable future.

“The real harm is that we have the probability that things are going to grind to a halt,” Lindenfeld said. “This is going to undermine the potential for real leadership in D.C. in ways that will hurt us for longer than we care to know.”